The present invention relates generally to systems and methods for the condition-based monitoring of machines. More specifically, the present invention pertains to monitoring the condition of heat exchange units.
In conducting a condition-based maintenance (CBM) program for machines, or components of machines, analysts using physical evaluation and a knowledge base, can make a decision on the relative health of various components of the machine, or the machine itself. Typically, sensors are mounted at various locations on a machine to detect at least one, or more, physical phenomenon that is produced by the operation of the machine. The detection and analysis of the phenomena is ideally performed in-situ in order to provide a real-time analysis of the condition of the machine or component of the machine.
For example, vibrations emanating from the operation of a bearing assembly are detected using an accelerometer placed in proximity to the bearing. The vibrations of the bearing assembly produce a vibrational energy that is measurable in amplitude and frequency. Data obtained during the operation of the bearing assembly is compared to data stored within a database that usually includes a plurality of parameters relative to the operation of the bearing assembly. The parameter limit data is obtained from an analysis of the bearing assembly. An analyst assesses the condition of the bearing assembly by comparing the operational data of the bearing assembly to the stored parameter data.
Other physical phenomena such as sound or temperature may also be detected and analyzed for condition based monitoring of a machine. For example, the temperature and flow rate of fluid media in a heat exchanger may be analyzed for determining the health of the heat exchange unit. A heat exchanger performance monitor is disclosed in U.S. Pat. No. 4,766,553 (hereinafter referred to as the “'553 Patent”). The system of the '553 Patent discloses the use of temperature transmitters mounted to an evaporator or condenser, which are electronically linked to software programmed to input temperature readings into equations for analysis of the performance of the heat exchanger.
At least with respect to mobile assets, such as locomotives, automated CBM has not been utilized for assessing the health of a heat-exchange unit. The monitoring of a heat exchange unit typically includes a subjective analysis of the temperature output of the exchange unit, which may lead to inconsistent results from analyzer to analyzer. In the operation of similar machine assets, such as in the operation of a fleet of mobile assets subject to a condition based monitoring system, the generation of parameter threshold requirements for individual heat exchange units may not be practical. In addition, condition-based monitoring of stationary heat exchange units does not factor changing ambient environmental conditions into the analysis of the health of a unit.
With respect to locomotives, non-contact infrared temperature sensors have been used to take temperature readings of components of a locomotive. Specifically, infrared sensors have been mounted subjacent a railroad track at locomotive service stations. When the locomotive is stopped for servicing at a station, the infrared sensors are activated and detect the temperature of bearing assemblies of the locomotive wheel casings. However, such sensors may not be practically installed for operation with internal components of some machines. Indeed, some internal operating components cannot be practically analyzed using conventional stationary contact or non-contact sensors.